* {
    padding: 0;
    margin: 0;
    list-style: none;
    box-sizing: border-box;
}

.content {
    width: 1000px;
    height: 600px;
    position: relative;
    margin: 50px auto;
    font-size: 0;
}

.leftImg {
    display: inline-block;
    width: 490px;
    height: 510px;
    margin-right: 18px;
    position: relative;
    background-image: url(./images/imgA_2.jpg);
    background-repeat: no-repeat;
    background-position: center;
    background-size: cover;
}

.mask {
    width: 230px;
    height: 230px;
    position: absolute;
    /* top: 0; */
    /* left: 0; */
    opacity: 0;
    background-image: url(./images/bg.png);
    pointer-events: none;
    /* mask不参与鼠标事件，解决了mask抖动的问题 */
}

.rightImg {
    display: inline-block;
    width: 490px;
    height: 510px;
    background-image: url(./images/imgA_3.jpg);
    background-repeat: no-repeat;
    opacity: 0;
}

.imgWrap {
    width: 490px;
    height: 90px;
    text-align: center;
}



.imgWrap ul li {
    width: 60px;
    height: 60px;
    display: inline-block;
    margin: 15px 10px;
    border: 2px solid #eee;
    background-image: url(./images/imgA_1.jpg);
}